Intake manifold for internal-combustion engines



May 11 1926.- 1,584,245

G. c. RoBmsoN INTAKE MANIFCLD FOR INTERNAL COMBUSTION ENGINES Filed August 1. 1924 If 2 I "L 2/ i' f w H, gg a a," AI/'6 a fl: 2 Q3 V Y 5 L 7 INVENTOR.

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UNITED STATES islets tries.

GERARD G. ROBINSOET, OF DETROIT, MICHIGAN.

Application filed August 1, 1924*. Serial N'o. 729,430.

This invention relates to intake manifold construction for internal combustion engines. The principal object of the invention is to provide a construction of simple and unique character in which a practically steady flow of heated air is delivered into the intake manifold and mixing with the fuel charge passing through the manifold and in which the volume of the heated air delivered is practically constant at all normal engine speeds.

A further object of the invention is to provide an intake manifold having certain definite cubical content relative to the horsepower of the internal combustion engine with which it is to be utilized in which is introduced an electric element for heating a stream of air which flows into and mixes with the main air and fuel charge and in which the heating element is shielded preventing a direct contact of the main fuel and air charge therewith.

A further object is to provide a manifold construction adapted to receive an electric heating element which is bodily removable from the manifold and in which the element is arranged about an air tube and further is enclosed within a metal shell, all of which parts are removable as a unit from the manifold. These general objects and other specific objects and features of construction of the invention are hereinafter more fully described and claimed, and the preferred form of construction of an intake manifold for an internal combustion engine embodying my invention is shown in the accompanying drawings in which- Fig. 1 is an elevation partly in section of an intake manifold embodying my invention.

Fig. 2 is a vertical section of the heating element on an enlarged scale.

The manifold as herein shown is adapted for use in an internal combustion engine utilizing as a fuel, air and liquid hydrocarbon. lVith such character of fuel charge, the most efficient results are afforded where there is a perfect mixture of the fuel and air and this may be secured by heating the fuel charge subsequent to the mixture of air with the liquid hydrocarbon. This mixture is performed by the usual carburetor which is to be understood as being connected with the manifold 1 at the end 2 which, in the construction here shown in full lines, has a right angle bend leading to the vertical duct of the manifold. This character of construction is adapted for use wit-h some types of carburetors others of which require connection to a horizontal flange rather than the vertical type of flange as shown in full lines in Fig. 1. To accommodate other types of carburetors, the intake manifold may have a downwardly bent end as shown by dotted lines in Fig. 1. In either case the vertical part of the manifold has at one side of the intake end 2 or 2 a boss 3 threaded to receive a plug 4, which plug has a boss 5 at the inner end. The plug is hollow as will be understood from the drawing and a tubular porcelain member 6 is inserted through the plug and extends for a considerable distance into the manifold when assembled therewith as shown. This porcelain 6 has a head 6 which seats against a shoulder 7 provided therefor at the outer end of the nut. Through the interior of the porcelain tube 6 is a metal tube 8 which extends somewhat below the nut t at the lower end and extends beyond the inner end of the porcelain tube. At the lower end of the tube 8 is a nut 9 which engages packing 10 in the recess for the head 6 of the porcelain tube and a jamb nut 11 is provided on the lower end of the tube and between the nuts 11 and 9 is secured the electric circuit wire 12. The extreme lower end of the tube is provided with a cap 13 having an aperture 14 and this nut is threaded on the end of the tube 8 so that it may be turned and the aperture 1 1 therein brought into or out of registration with a companion aperture in the side of the tube 8. By turning this nut 13, more or less air is allowed to pass through the tube 8. The upper end of the tube, as shown more clearly in Fig. 2, is shaped to provide a venturi 15 and this tends to deliver air ininverted coned form in the interior of the vertical duct of the manifold. An impervious metal casing 16 of tubular form is positionedon the boss 5 of the nut 4: and is held in place thereon completely enclosing the porcelain insulation and the resistance element 17 wound thereon. This casing 16 has an aperture at the upper end to receive the porcelain insulating member 18 above which is a nut 19 threaded on the tube 8 and by means of which this casing 16 is fixedly secured in place. The heating element 17 is the usual electric resistance ele ment and has the lower end for instance at 26 in electrical contact with the metal boss 5 of the nut- 4 and is thus grounded. The

upper end of the wire at 21 is wound about the metal tube 8 at the end of the porcelain insulation and is held in place by a nut 22 threaded on the tube 8. Any type of which element may be utilized with this device as may be found desirable. I prefer to provide a switch of the character diagrammatically illustrated in Fig. 2 which has two movable switch members and one of these switches is provided with a resistance element 23 across the contacts and the other is unprovided therewith. The circuit wire connects with the battery which is to be understood as being grounded is usual and extends to the contact element 24L and current passes through the switch element 25 when closed to the contact member 26 and thence to the contact 2'? through the line 40 directly connected with said contacts and thence through the switch element 28 thereof to the remaining contact 29. To this contact 29 is connected the electric wire 12 which connects with an end of the heating element 1'? through the tube 8. l i ith the switch member 25 closed, full flow of current from the battery passes through the points 24, 26, 27 and 29 to the element. Upon movement, the element 25 to break the contact between the points 2% and 26, r duced current will flow through the resistance el ment 22 preventing waste of the electric current which vshould be unnecessary after the element has been energized and the engine started.

By the arrangement described, on starting the engine, the full flow of current is passed through the heating element 17 and this tends to heat the porcelain and to thoroughly heat the air tube 8 passing centrally therethrough so that upon starting the motor a very hot flow of air is secured through the tube which, due to the vent iri 15 at the end thereof, forces the air passing through the tube to flow in a substantially coned form in the vertical duct, and the fuel charge at this time passing through the inlet end 2 or 2 of the manifold flows through this heated stream of air from the tube 8, This vapor izes the liquid fuel in the fuel charge and produces a proper mixture for delivery to the engine cylinders which are to be understood as being connected with the manifold at the ends 30 and 31.

I have found that the best results of operation of the engine of the four cylinder type at all usual speeds is secured with a manifold having a. cubical content of approximately one and two-tenths cubic inches per horsepower which is somewhat greater than has been the practice heretofore. With a six or eight cylinder engine the cubical content of the intake manifold may be as great as two (2) cubic inches per horsepower. With a manifold of this larger capacity each cylinder does not rob the manifold of the entire fuel charge, and this cubical capacity is found particularly desirable in conjunction with the heating element having an air tube passing there through to deliver heated air into the fuel charge in the intake manifold. The fuel flow into the intake manifold through the port 2 or 2 with which the carburetor is attached is controlled as is usual with such carburetors by a butterfly valve and by in crease or decrease of fuel flow, the engine speed is varied but such variation in fuel flow does not materially vary the flow of air through the air tube 8. By shielding the heating element by means of the impervious casing 16, the fuel charge is not materially heated by the element and the injection of heat into the fuel charge is practically solely by means of the air tube 8.

it is therefore evident that the device is simple in construction and is eiiicient for the purpose, that the heating element is readily removable as a unit for repair, and that consumption of the battery charge is small during operation of the engine particularly through use of the resistance element 22 under normal operation in which condition the switch 25 is open and the switch 28 closed in the special type of switch here shown but other types of switches, however, may be utilized without departing from the spirit of this invention.

Having thus briefly described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Batent of the United States is 1. In combination, an intake manifold consisting of a duct for the passage of a fuel charge, an electrically heated element in the duct, and a tube heated by the ele ment open to atmosphere at one end and dis harging into the duct at the other.

2.111 combination, an intake manifold for internal combustion engines consisting of a duct for the passage of a fuel charge and having branches for connection with an engine and provided with a main inlet at the lower end of the said vertical portion, an electrical heating element extending into the vertical portion of the duct, and a tube of small diameter heated by the element opening to atmosphere at one end and discharging into the duct above the point of entrance of the fuel charge therein.

3. in combination, an intake manifold for internal combustion engines consisting of a ductfcr passage of a fuel charge having branches at the upper end for connection with an engine and having an inlet extending outwardly from the duct at the lower end, an electrical heating element insertable into the lower end of the duct in longitudinal alignment therewith, an impervious shield enclosing said element, a tube extending through the heating device heated by the said element opening to atmosphere at the outer end and discharging into the duct above the point of entrance of the fuel charge thereinto, and an electric circuit including a source of electrical energy for supplying current to the element.

4:. The combination of an intake manifold for an internal combustion engine, consisting of a vertical duct for the passage of a fuel charge having branches at the upper end for connection with the cylinders of an engine, a threaded opening at the opposite end in alignment with the axis of the duct, a side opening for connection with a carburetor through which the fuel charge passes into the duct, a heating element consisting of a base for threaded engagement in the said threaded aperture, an electrical heating element consisting of a hollow insulating tube and a wire of resistance material the-reabout, the said wire forming part of an electrical circuit, an air tube extending through the plug and opening to atmosphere at the bottom end and discharging into the duct above the intake end thereof, and an impervious shield about the element supported on that plug.

5. The combination of an intake manifold for internal combustion engines consisting of a duct for the passage of a fuel charge and having a main fuel inlet, an electrically heated element in the duct, a tube heated by the element throughout the major portion of its length shielded from contact with the fuel charge passing through the duct, the said tube opening to atmosphere at one end and discharging into the duct at the other end.

6. The combination of an intake manifold for internal combustion engines having an inlet at one end for the fuel charge and outlet branches at the other end adaptcd for connection with the respective cylinders of the engine, an electrical heating element extending into the duct, a tube heated by the element opening to atmosphere at one end and discharging into the duct at the other, and an impervious shield enclosing and shielding the tube and element from influence of cooling effect of the inflowing charge.

7 The combination of an intake manifold for internal combustion engines consisting of a duct for the passage of a fuel charge, an electrically heated element in the duct, a tube heated by the element and open- .ing to atmosphere at one end and discharging into the duct longitudinally thereof at the other end, the said discharge end of the tube being of the form of a venturi.

8. The combination of an intake manifold for internal combustion engines consisting of a duct for the passage of a fuel charge, a tube extending into the duct longitudinally thereof opening to atmosphere at one end and discharging into the duct at the other, the said discharge end having the form of a venturi, and means for heating the air passing through the tube.

9. The combination of an intake manifold for internal combustion engines consisting of a duct for the passage of a fuel charge having a main fuel inlet at one end and branch conduits for connection with the cylinder of the engine at the other end, and an air tube extending longitudinally of the duct from its lower end adjacent the inlet, said tube being open to atmosphere at one end and discharging into the duct at the other, and means for heating the air tube, the cubical content of the manifold being not less than one cubic inch per horsepower of the engine with which it is to be utilized, and the said air tube being of small diameter whereby the vacuum in the duct occasioned by operation of the engine is not materially affected.

In testimony whereof, I sign this specification.

GIRARD G. ROBINSON. 

